<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        h1{
            color: red;
        }
        .c1{
            color: green;
        }
        .c2{
            font-size: 20px;
        }
        #x1{
            color: purple;
        }
    </style>
</head>
<body>
    <h1>你好</h1>
    <h1>666</h1>
    <p class="c1">段落1</p>
    <p >段落2</p>
    <p class="c1 c2">段落3</p>
    <p id="x1">id选择</p>
    <hr>
    <style>
        .fa h2{
            color: #9acd32;
        }
        .fa>h2{
            font-size: 12px;
        }
    </style>
    <div class="fa">
        <h2>2级标题1</h2>
        <div>
            <h2>33333</h2>
        </div>
    </div>
    <h2>2级标题2</h2>
    <hr>
    <style>
        .xi:hover{
            color: red;
            cursor: pointer;
        }
    </style>
    <p class="xi">西游记</p>
</body>
</html>